Believers in the Trinity probably assume that Jesus Christ and his apostles taught it and that it is a Bible teaching. But it is not. The New Catholic Encyclopedia acknowledges: “The formulation ‘one God in three Persons’ was not solidly established, certainly not fully assimilated into Christian life and its profession of faith, prior to the end of the 4th*century [hundreds of years after Jesus and his apostles were on earth]. .*.*. Among the Apostolic Fathers, there had been nothing even remotely approaching such a mentality or perspective.”
On the other hand, hundreds of years before Jesus Christ came to earth as a man, the trinity teaching was firmly entrenched among peoples whose religions were based on mythology. For example, the ancient Egyptians worshiped the trinity of Osiris, Isis (his wife), and Horus (his son). And the Hindus, even down to this day, worship a trinity made up*of the three-headed Trimurti of Brahma, Vishnu, and Siva.
Jesus Disciples would have had NOTHING to do with such a teaching.